Air compressor discharge line cleaning and unloading systems



7 July 21, 1959 T. J. MCSWEENEY, SR 2, I

AIR COMPRESSOR DISCHARGE LINE CLEANING AND UNLOADING SYSTEMS Filed Oct. 17, 1957 I 2 Sheets-Sheet 1 INVENTOR. fiomasclxl lclweelzqg 81.;

By fwiq w A TTORNEYS.

July 21, 1959 T. J. McSWEENEY, SR 2,895,665

AIR COMPRESSOR DISCHARGE LINE CLEANING AND UNLOADING SYSTEMS Filed Oct. 17, 1957 2 Sheets-Sheet 2 Ffi 2 INVENTOR. 71201720.; :IMcXweenqgSa,

BY g f ATTORNEYS.

United States Patent AIR COMPRESSOR DISCHARGE LINE CLEANING AND UNLOADIN G SYSTEMS Thomas J. McSweeney, Sr., Wilmington, Del.

Application October 17, 1957, Serial N 0. 690,737

1 Claim. (Cl. 230-24) This invention relates to discharge line cleaningand unloading systems for compressed air generating apparatus in which compressed air is delivered by a governorcontrolled compressor to a storage reservoir or reservoirs, for example, on a locomotive or a self propelled railway vehicle for use in brake operation of trains.

The chief aim of my invention is to provide, in connection with compressed air generating apparatus, simple and reliable means which is operable automatically at the beginning of each unloading and cut-out cycle of the compressor to rid the system of water, oil and other foreign matter passing through the compressor before these contaminants can reach the storage reservoir or reservoirs, with a view to reduce the heat load on the compressor and to minimize wear such as would be caused thereby.

As more fully disclosed hereinafter, the purposes of my invention are achieved by utilization of an air operated dump valve and a non return check valve between the air compressor and the main storage reservoir of the apparatus. Each time the compressor governor functions to unload or cut out the compressor, the dump valve is actuated to open the discharge line (commonly called the after cooler piping) between the compressor and the check valve to the atmosphere, and thereby rid this section of the pipe of all contaminants. When the governor functions to start the loading cycle of the compressor, the dump valve automatically closes and the compressor starts to build air pressure in the discharge line beginning only against atmospheric pressure.

Other objects and attendant advantages will appear from the following detailed description of the attached drawings, wherein:

Fig. 1 shows, more or less diagramatically, a compressed air generating apparatus conveniently embodying my invention; and

Fig. 2 is a View similar to Fig. 1 showing the apparatus in a dilferent stage in the cycle of compressor operation.

With more detailed reference to these illustrations, the numeral 1 comprehensively designates a conventional multi-cycle stage-wise air compressor commonly used on locomotives, which is diagrammatically shown as having a high compression cylinder 2 and two low compression cylinders 3 and 4. The air compressor may be, for example, of the 3-CDB Type for Locomotives, disclosed in an Instruction Pamphlet No. 50025 of the Westinghouse Air Brake Company of Wilmerding, Pennsylvania, to which reference may be had as to the unloading valves. The governor for the compressor, indicated at 5, is connected by a pipe 6 to the unloading valves of the respective cylinders of the compressor. As usual in an apparatus of this sort, the compressed air is conducted from the high pressure cylinder 2 of the compressor 1 to a main storage reservoir through a discharge pipe line 8 wherein is interposed an after cooler conventionally represented as 9. Also after common practice in the art, the governor 5 is connected, by a branch conduit 6a, to the outlet conduit 7a of the storage reservoir 7, the governor being thus responsive to the pressure of the air in said reservoir.

The means which I have devised for automatically ridding such an apparatus of water, oil and other foreign matter passing through the compressor before these contaminants can reach the storage reservoir 7, includes a non-return check valve 10, and a dump valve 11 in the body of which a ported partition 12 sets apart an upper chamber 13 and a lower chamber 14, said upper chamber having a lateral exhaust aperture 15 open to the atmosphere. 1 As shown, the upper chamber 13 of the dump valve 11 is in communication with the compressor governor pipe 6 by way of a branch pipe 16, and the lower chamber 14 of said valve is in communication with the air compressor discharge pipe 8 by way of a branch pipe 17 which connects with the pipe 8 at a point relatively close to the compressor. Disposed within the upper chamber 13 of the dump valve 11 is a piston 18 which is yieldingly urged upwardly by a spring 19, and disposed in the lower chamber of said valve is a closure element 20 which is normally held to the seat around the port in the partition 12 by a separate spring 21, said closure element having an upwardly extending axial stem projection 22 which reaches into close proximity to the piston 18 in the normal condition of said valve.

Operation In Fig. 1, assume that the compressor 1 is in operation and delivering compressed air through the line pipe 8 and the after cooler 9 past the check valve 10 (which at this time is held open by the pressure of the air) into the main reservoir 7. Also at this time the closure element 20. of the dump valve 11 is held, with the assistance of the spring 21, in engagement with the seat around the port in the partition 12. The full pressure of the air in the discharge line 8 by way of branch pipe 17 also tends to keep the closure element 20 tightly on its seat. During this stage of compressor loading there is no pressure in the compressor governor pipe 6, branch pipe 16 or in the upper chamber 13 of the dump valve 11.

When the air in the reservoir 7 reaches a predetermined pressure, the governor 5 operates to unload the compressor by admitting air pressure into pipe 6 to the unloading valve of all cylinders of the compressor. The resultant drop of pressure in the discharge pipe 8 causes check valve 10 to close and prevent escape of the air stored in the reservoir 7. The pressure of air in governor pipe 6 and branch pipe 16 to upper chamber 13 of the dump valve 11 causes the piston 18 to be depressed as in Fig. 2. As a consequence, the closure element 20 of the dump valve 11 is depressed against the force of the spring 21 as in Fig. 2 as the piston 18 descends, to open the port in the partition 12. Under these circumstances, water, oil and other contaminates entrained in the air initially discharged from the compressor 1 will be by-passed through the branch pipe 17, the lower chamber 14 of the dump valve 11, the now open port in the partition and the lower part in the upper chamber 13, and be forcibly ejected through the lateral aperture 15 in the body of the valve. These conditions will prevail until the pressure of the air in the storage reservoir 7 drops to the predetermined cutting in point of the governor, at which time the air pressure in the governor pipe will be exhausted to atmosphere closing the unloading valves on the cylinders of the compressor and as a result of the corresponding loss of pressure in the branch pipe 16 and upper chamber 13 of the dump valve, the piston 18 responding to the pressure of spring 19 will return to its normal position. The closure element 20 will be forced to its seat by the action of spring 21 and thus prevent further escape of air through the aperture 15 of said valve. It will thus be seen that through my invention, any contaminants entrained in the air discharge line of the compressor 8 between the compressor and the check valve 10, as well as any contaminants passing through the compressor during the unloading cycle are expelled and therefore prevented from reaching the main storage reservoir 7 and the brake line of the train.

In standard compressed air generating apparatus ordinarily used on railway vehicles, the air discharge line pressure ranges from 125 lbs. (cutting in point of the governor) to 140 lbs. (cutting out point of the governor). Accordingly, when the compressor begins to charge the apparatus, the compressor works against a pressure on the discharge line beginning at 125 lbs. (cutting in point of the governor). Furthermore, the contaminants, passing through the compressor are conveyed to the main storage reservoir on the locomotive and also to the storage reservoirs of the entire braking system on the entrained cars requiring these reservoirs to be scavenged frequently by opening of the individual air relief cocks with which they are ordinarily provided. By way of contrast, it 'will be seen that, through the present invention, the compressor, in starting, operates only against atmospheric pressure or approximately 15 lbs., with consequent easement of the load on the compressor and minimization of wear.

While in accordance with the provisions of the statutes, I have illustrated and described the best forms of embodiment of my invention now known to me, it will be apparent to those skilled in the art that changes may be made in the form of the apparatus described without departing from the spirit and scope of the invention as set forth in the appended claims, and that in some cases certain features of my invention may be used to advantage without a corresponding use of other features.

Having thus described my invention, I claim:

In a compressed air generating apparatus for a railway train brake system or the like, a storage reservoir; a compressor having a cylinder with an unloading valve; a governor interposed in a conduit extending between the outlet of the reservoir and the compressor cylinder; an after cooler interposed in a discharge pipe leading from the compressor to the storage reservoir; a check valve interposed in the discharge pipe at the inlet of the storage reservoir; a dump valve having a ported partition between two chambers, an actuating piston in one of said chambers, a lateral exhaust port in the valve body beyond said piston, and a closure element in the other chamber operable by the piston but normally spring-biased into engagement with a seat around the port in said partition; a branch conduit extending from the conduit aforesaid at a point between the compressor and the governor; and a branch pipe leading from the discharge pipe at a point immediately adjacent the compressor and connecting into the aforesaid other chamber of the dump valve whereby,

upon operation of the governor to unload the compressor, after a predetermined pressure of air in the reservoir is reached, the piston of the dump valve is actuated to move the closure, element of the dump valve from its seat for expulsion of the contaminants from the compressor and from the after cooler.

References Cited in the file of this patent UNITED STATES PATENTS 1,215,071 Steedman Feb. 6, 1917 1,484,673, Redfield Feb. 26, 1924 1,793,633, Parke Feb. 24, 1931 2,279,431 Aikrnan Apr. 14, 1942 2,301,034 Freeman et al. Nov. 3, 1942. 2,535,760 Sherman et al. Dec. 26, 1950 2,717,612 Aifleck Sept. 13, 1955 2,739,605 Smith Mar. 25, 1956 2,787,411 Hughes Apr. 2, 1957 

